How can we apply urban research more effectively to make better cities, towns and suburbs?

The 62nd International Making Cities Livable (IMCL) conference in Potsdam, Germany, October 15-18, will take up this important question, among others

ABOVE, the "new urbanist" neighborhood of Orenco Station, in the Portland, Oregon region, is one of many that offer compelling research findings about their positive results. Orenco Station showed a reduction in trip generation and parking demand of over half of ITE manual standards, translating into significant financial and ecological benefits. Photo: Michael Mehaffy (former project manager for the master developer)

A fascinating new research project at the University of Notre Dame in the USA is addressing a thorny problem: a growing body of research is documenting the many significant benefits of compact, walkable, mixed cities, of the kind that are common in many parts of Europe -- but the lessons are not getting through to the majority of building projects around the world.

The findings are compelling: the characteristics of "the new urbanism" -- that is, the patterns of traditional city form adapted to a contemporary context -- can convey significant, measurable economic, social, environmental, and health benefits.

Among the findings:

• Walkable mixed-use or new urbanist development can save an average of 38 percent on upfront costs for new construction of roads, sewers, water lines and other infrastructure, generate 10 times more tax revenue per acre than conventional suburban development, and can reduce the costs of ongoing delivery of public services including police, ambulance and fire by an average of 10%

• New urbanist development can reduce trip generation and parking demand by over half of ITE manual standards, resulting in significant savings to municipalities, businesses and homeowners, and reducing negative impacts on land, water and air quality.

• Homes in New Urbanist neighborhoods command price premiums of up to 14.9%, reflecting high demand for walkability and mixed-use development. (This also indicates the need for more supply to ease demand and lower prices.)

• A 5% increase in walkability leads to a 32.1% increase in time spent walking, a 6.5% reduction in vehicle miles traveled, and a measurable decrease in air pollutants.

• Residents of walkable neighborhoods are approximately 50% more likely to achieve recommended levels of physical activity compared to those in less walkable areas. Additionally, they are about 24% less likely to experience obesity.

• Residents of walkable neighborhoods report significantly and measurably higher levels of social trust and civic engagement than those in car-dependent suburbs.

• Streets in compact, walkable urban areas are measurably safer than sprawling suburbs, due to lower vehicle speeds and pedestrian-friendly street designs, resulting in fewer deaths and injuries.

• Older adults living in walkable areas experience measurably lower rates of depression, stress- related illnesses, and dementia.

• Traditional walkable and mixed-use development reduces greenhouse gas emissions by 20–40%, making it a key strategy for fighting climate change.

• Auto-oriented developments, including big-box retail, are linked to higher rates of traffic-related injuries and even deaths, while pedestrian-friendly retail areas see fewer crashes.

• High-tech firms prefer compact, walkable urban environments, boosting economic growth.

• Traditional street patterns—such as those found in historic city centers—are associated with lower crime rates, while modern suburban layouts show higher rates of burglary and street robbery.

• Compact development reduces infrastructure costs by 38% and generates 10 times more tax revenue per acre than conventional suburban sprawl.

• Most members of the public strongly prefer traditional and vernacular architecture, and there is evidence that those characteristics are more supportive of popularity and success in urban development.

The research project, commissioned by the Notre Dame School of Architecture, has compiled a representative database of over 220 research papers in a wide range of disciplines, including medicine, psychology, anthropology, sociology, ecology, economics, law, policy, and other fields. The research assesses the impacts of new urbanism (or other related variants of "traditional city form") on health, well-being, safety, social activity, economic costs and benefits, and the natural environment.

IMCL and Lennard Institute Executive Director Michael Mehaffy is leading the research project, as part of The Center for Housing and Community Regeneration at the School of Architecture, University of Notre Dame, led by Professor Marianne Cusato. Contributors include fellow Senior Researchers David Brain and Jim Brainard, both part of the CH&CR initiative. Jim Brainard is the long-time mayor of Carmel, Indiana, an IMCL award-winning example of a suburban transformation into a national model of livability. Jim Brainard is also a board member of the Lennard Institute/IMCL, and David Brain, a sociologist, is a noted speaker at several IMCL conferences. Dean Stefanos Polyzoides, who commissioned the research, is a co-founder of the Congress for the New Urbanism.

The upcoming 62nd conference of the IMCL, to be held October 15-18 in Potsdam, Germany, will explore the range of research findings, as well as the larger challenge of communication and implementation.

A key conclusion is that the research is there, but in fragmented form. What is needed is to put together, and to share, the "big picture" -- how all these benefits work together as a system, and often contribute more in combination than any one of them in isolation. That's one benefit of this kind of survey research.

Another important outcome of survey research is to identify key gaps in the research, and that is certainly an important outcome of this project. One of the most notable gaps is in project level research, assessing the achievements and goals of specific projects.

Some of this research does exist -- and it is very encouraging. Portland's Orenco Station, for example, showed reductions in automobile trip generation and parking demand of over half of the Institute of Transportation Engineers' standards, contributing to significant economic and ecological benefits. The community also showed significantly higher indications of "social capital" (levels of trust and cooperation between residents) as well as much higher rates of walking by residents. (IMCL Executive Director Michael Mehaffy was the project manager for the master developer of Orenco Station.)

The Notre Dame research project has also documented many economic benefits of new urbanist development. (Reductions in parking demand and trip generation are two of the many examples, since they reduce costs of land, construction, and maintenance.) At the same time, the project also documented many of the remaining barriers to new urbanist development. These obstacles make New Urbanism much harder to implement, and they constitute hidden subsidies for “business as usual.” This too is a critical area of much-needed follow-up research, providing much-needed implementation streamlining for policy and practice.

One of the more surprising barriers may be our own misunderstanding as practitioners of the usefulness of urban research. There are common misconceptions about the role of research in relation to practice. One is the belief that a given finding must be conclusive – must be “proof” – or else the effort to engage the research is futile.

But in the world of research, rarely does one finding conclusively “prove” a fact. In most fields of research, the goal is not “proof” but the “preponderance of evidence” – that is, we develop and confirm our theories as guides to our practice, unless and until they are disproven. Until then, our goal is to show that our theory is better than the others out there – it is more likely to “deliver the goods,” in whatever field.

Like any practitioner, advocates of walkable mixed use and new urbanism certainly have their own theories about the patterns and practices that will result in better outcomes for human beings, as judged by them, and by us all. We have the same obligation to demonstrate the validity of our theories as any professional, if we are to be credible, and to drive successful reform with persuasive evidence to rebut our critics.

Perhaps our role as practitioners can be compared to that of medical practitioners. While we usually don’t conduct the research ourselves, it’s important to be aware of it, and to be able to communicate its findings to our “patients” – the governments, businesses, and citizens that we serve. Too often, however, the research doesn’t find its way into practice and policy, leading to a lack of progress on critical urban issues. It’s as though a series of new life-saving medicines were discovered, only to be ignored by practitioners.

The great urban journalist Jane Jacobs may have put it best when she accused her generation of planners of practicing “pseudo-science” – seemingly almost neurotic in their “determination to imitate empiric failure and ignore empiric success.”

We have the empirical success to accumulate, to show, and to learn from – and it’s urgent that we do so.

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NOTE: A version of this article previously ran on the journal CNU Public Square. Our thanks to editor Rob Steuteville.

New Research By Cambridge-Led Team Shows How Building Façades Trigger Visual Stress

Cambridge researcher and IMCL speaker Cleo Valentine, along with her colleagues at Cambridge, The University of Essex and Universitat Autónoma de Barcelona, find disturbing health implications

Left, the Marsham Towers in London, by the architect Eric Bedford, remarkably unpopular and demolished in 2002. Right, the Barcode Project in Oslo, representing "state of the art" contemporary architectural design. While such compositions might be intended as worthy artistic expressions by the architects, they can also have profoundly negative impacts on people who must experience them unintentionally. Images: Malcoml Campbell via Wikimedia Commons; Bjørn Erik Pedersen via Wikimedia Commons.

EDITOR'S NOTE: This post is part of a series of discussion posts for the upcoming 62nd International Making Cities Livable (IMCL) conference.

CAMBRIDGE, UK - Can a building make you feel uncomfortable – even unwell – without your full awareness of the reason? According to a new study by researchers from the University of Cambridge and their collaborators, the answer is yes – and the reason may lie in how your brain unconsciously processes the visual patterns of architectural design.

In a new paper just published in the journal Buildings, researchers Cleo Valentine, Arnold J. Wilkins, Heather Mitcheltree, Olivier Penacchio, Bruce Beckles, and Ian Hosking reveal how repetitive, high-contrast patterns commonly used in modern façades can cause subtle yet measurable strain on the human visual system. Using artificial intelligence (AI) and computational tools, they find evidence that some architectural designs might literally stress out our brains.

Cleo Valentine, the lead researcher, is a past speaker at the International Making Cities Livable (IMCL) conference series, and she is scheduled to participate in the next conference in Potsdam, Germany, October 15-19, 2025.

The Brain and the Built Environment

As the authors note, it is well known that our surroundings affect our mental and physical health. Sunlight, noise levels, and even ceiling height have been shown to influence mood and behavior. This study explores how the visual patterns encountered every day – especially on building exteriors – interact with the brain’s processing systems.

The authors suggest that the human visual system evolved in natural environments with soft, irregular patterns, but modern architecture often features repetitive, high-contrast designs that deviate from these natural characteristics. For at least some people, exposure to the modern patterns may lead to discomfort, headaches, and even more serious neurological reactions.

This phenomenon, known as visual stress, has been documented in individuals with migraines, photosensitive epilepsy, and sensory processing disorders. However, the researchers propose that even people without these conditions might experience subtle strain from prolonged exposure to visually stressful environments.

A New Way to Measure Visual Discomfort

Studying how architecture impacts the brain is challenging. Traditional methods rely on artificial laboratory patterns – like black-and-white stripes – or surveys asking people how they feel when looking at photos of buildings. These approaches often lack either realism or scientific rigor.

To address these challenges, the team developed a hybrid method. They used Midjourney, a generative AI tool, to create a series of nine different building façades. Each design was systematically varied in features like contrast, repetition, geometric shapes, and spatial frequency (a measure of how often elements repeat in a visual field).

The designs were then analyzed using the Visual Stress Analysis Tool (ViStA), a computational system that measures how much an image deviates from the statistical patterns found in natural scenes. When an image contains too much energy at certain spatial frequencies, especially around three cycles per degree (a scale to which human vision is highly sensitive), it is more likely to induce discomfort.

The researchers liken this to audio feedback for the eyes: when patterns are too regular and high-contrast at certain scales, they may overload the visual cortex, leading to effects ranging from mild irritation to, in extreme cases, migraines or seizures.

What They Found

The findings reveal that façades with highly regular, high-contrast patterns showed the strongest indicators of visual stress. In particular, designs featuring vertical slats or metal screens repeated at around three cycles per degree produced the highest stress metrics.

One façade with closely spaced vertical wooden slats (at precisely three cycles per degree) showed peak residuals of 1.1 x 10^10 in the ViStA analysis, far exceeding the baseline design. Another, with layered vertical metal screens, also produced elevated stress markers, even though its patterns repeated at a higher frequency.

Implications for Architects and Urban Designers

This research emerges at a time when cities around the world are grappling with the health impacts of dense, visually intense urban environments. Architects often favor clean, repetitive lines for aesthetic or functional reasons, but the study suggests such choices may have unintended consequences.

The authors argue that not all repetition is bad, but designers should be aware that certain patterns, especially when combined with high contrast and reflective materials, can create environments that subtly fatigue the human brain.

The methods developed in this study could serve as a design aid. The ViStA tool can generate “heat maps” of façades, highlighting areas likely to cause visual stress. Designers might use this feedback to refine their projects, balancing aesthetic goals with neurophysiological well-being.

Limitations and Next Steps

While the study provides valuable insights, the authors caution that it is an early step in a complex field. Their analysis relied on static, two-dimensional images, which do not fully capture the dynamic way people experience buildings as they move through space.

Future research plans include expanding the work using virtual reality and real-world studies. Ultimately, the team aims to link computational predictions with physiological measurements from real people, such as heart rate variability and brain activity, to validate and refine the model.

The researchers are also exploring equity issues. They suggest that visually stressful environments may disproportionately affect neurodiverse individuals and those in lower-income neighborhoods. Future studies could map visual stress across urban areas to inform more inclusive design policies.

Rethinking the Visual Language of Cities

This study highlights an important idea: architecture is not just about how buildings look, but how they make people feel at a neurological level. It adds to a growing body of research on the impact of the built environment on health and well-being. (Another example is the research of UCL Professor of Neuroaesthetics Semir Zeki, also a former speaker at the IMCL, who has noted that the experience of beauty in architecture can "nourish the emotional brain" and is "not a luxury, only a necessity".)

As cities grow and design trends evolve, integrating insights from neuroscience may lead to environments that are not only beautiful but also healthier for the mind. These and other findings indicate that while architects have long considered light, sound, and space, they now might benefit from thinking about the visual patterns people process every day. Even small changes in design could make cities and buildings healthier for everyone.

The next time you find yourself squinting at a building or feeling inexplicably uneasy in an urban street, your brain could be sending a message: it's not you, it's the architecture that's the problem. We deserve better, and it's time to demand better.

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For more information about the upcoming IMCL Potsdam conference and travel logistics, please visit https://www.imcl.online/potsdam-2025.

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Begun in 1985, the International Making Cities Livable (IMCL) conference series, hosted by the Lennard Institute for Livable Cities, has become a premier international gathering and resource platform for more livable, humane and ecological cities and towns. Our flagship conferences are held in beautiful and instructive cities hosted by visionary leaders able to share key lessons. We are a 501(c)(3) public benefit corporation based in the USA, with alternating events and activities in Europe and other parts of the world.

Attendee comments about previous conferences:

“A wonderful conference.”

“It was brilliantly organized!”

“I left the conference encouraged - there are many challenges ahead of us,

but I am so invigorated by the tenacity of those stepping up to face them.”

“This is the best conference I've ever attended. There was much to take in;

so many people with exceptional experience.”

Why "A Building is Not a 'Tree'"

Christopher Alexander's classic 1965 paper applies to both the city scale and the building scale, with important new implications -- even aesthetic ones.

ABOVE LEFT: Alexander's classic 1965 paper, included in a 2015 anniversary book collection of essays about the work and its importance, by Sustasis Press. RIGHT: Three examples of the same urban density in three very different urban forms, with very different patterns of connectivity. Drawing from the UK Urban Design Task Force.

POTSDAM, GERMANY - The 62nd International Making Cities Livable (IMCL) conference will be held in this beautiful city in the Berlin region from October 15th to 18th, 2025. As with all IMCL conferences, a key topic will be the geometry of our built environment, and how it shapes our lives - often in unseen or under-appreciated ways. As Churchill famously observed, "we shape our buildings, and thereafter they shape us" - for better or worse.

One of the most important ways that our environment shapes our lives is in the connections it affords us -- to other people, to daily needs and resources, and to the life of the city. We all experienced the consequences of lost connections during the coronavirus pandemic, as we were forced into isolation. When we did come into contact with others, we were acutely aware of our level of connectivity, and the likelihood of transmission of the virus.

It wasn't the density per se of an urban environment that made it more likely to transmit the virus -- an unfortunate assumption by too many of us -- but the pattern of connectivity. The illustration at the top of this blog illustrates this point. It shows three different structures, each with the same density, but with very different patterns of connectivity.

The tall building at left, with its central elevator core, lobby and entry point, is more likely to bring people into direct contact than the rowhouse in the middle, where people can spread out on the street, and choose to connect or not. The perimeter block at right also has lower connectivity, although somewhat higher than the rowhouses.

This intuitive understanding of the relative connectivity is backed up by research. Epidemiologist Shai Linn has observed that the incidence of infectious spread can be high in tall buildings. He draws an analogy to the spread of coronavirus and other diseases in cruise ships: in both environments, people tend to crowd into common areas like stairwells, elevators and lobbies (and dining rooms too). In both environments, infections (of all kinds) can spread rapidly -- as they did during the pandemic.

There is a deeper problem with these singular, centralized spaces. Consider the structure of a tree, where all the branches, twigs and leaves are connected to each other only through the trunk. Similarly, in a tall building or a cruise ship, all the parts are connected through central elevators, stairways and common areas, with no other paths of connection.

By contrast, a web-network doesn’t have to concentrate everyone into central spaces, because there are other alternative paths of connection and disconnection. This is true even when a given unit of space has the same number of people, that is, the same “density.”

The drawing at the top illustrates the difference between the "tree" in the tall building at upper left, and the "web-network" in the other two examples. Such a web-network still allows people to remain in social proximity – able to practice what I have called “sociable distancing” – without being forced into the kind of uncontrolled adjacency that allows transmission of pathogens. People can more easily control their degree of connectivity to others, and when desired, reduce that connectivity. That's something that is important at all times, not just during a pandemic.

As it happens, the urban and architectural theorist Christopher Alexander described these two different classes of structure, the hierarchy or "tree," and the web-network, in a famous 1965 paper. Alexander, who is better known as the author of the classic book A Pattern Language, wrote in his paper that “A city is not a tree” – or at least, a good city is not. That is, the best cities are not dominated by centralized tree-like structures, but rather, they have many web-like sets of connections that he referred to as “semi-lattices.”

The web-network structure also does something even more important than allowing us to control whether we are too close to avoid transmission of disease. It creates multiple points of interaction and mixing. As Jane Jacobs wrote, this kind of mixing is essential to the dynamism and the vitality of cities, and buildings too.

An obvious example of a tree-like structure and its consequences can be seen urban street patterns. Many sprawling suburban communities show a tree-like pattern that is easy to differentiate from, say, the web-like grids of many older cities (as in the figure below). The trouble with tree-like patterns is that they force traffic into limited “choke points” where it becomes congested and hostile to pedestrians. This pattern doesn’t allow vehicles or pedestrians to connect through other shorter trips between the branches, as is the case with the web-network. That usually means neighborhoods with tree-like structures are not walkable, are not very well suited to transit, are more dependent on automobiles, and are more prone to traffic congestion, with the degraded livability that often brings.

ABOVE: The sprawling, “tree-like” pattern at the top of this drawing makes it much more difficult to travel to the different destinations by transit, or especially, by foot. The pattern at the lower part of the drawing is much more inter-connected, offering many more ways to move and connect. Drawing by The Prince’s Foundation.

For Alexander, as for Jacobs, there is an even more fundamental problem for cities organized as “trees.” Cities get their vitality and their dynamism from these interconnections — from the diversity of people who come into mutual contact, from the mixing of different activities and movements, and from the “overlaps” that happen when things are not neatly segregated into tree-like schemes.

Alexander concluded:

It must be emphasised, lest the orderly mind shrink in horror from anything that is not clearly articulated and categorised in tree form, that the ideas of overlap, ambiguity, multiplicity of aspect, and the semilattice, are not less orderly than the rigid tree, but more so. They represent a thicker, tougher, more subtle and more complex view of structure.

If good vibrant cities are not “trees,” what about buildings? It seems the same logic applies: at the scale of buildings too, and especially as they connect to the public realm, we should seek overlap, multiplicity of aspect, and the other characteristics that Alexander celebrates. We should seek buildings that are more fine-grained, with redundant connections to the street, rather than one centralized “tree trunk,” as tall buildings typically feature.

In structural terms, we can compare a tall building to a kind of “vertical cul de sac” – or a kind of vertical gated community, with all the same potential problems of that problematic structural form.

It’s often assumed — wrongly, as research has shown — that tall buildings are necessary to achieve higher population densities. Yet the three schemes at the top of the page all have exactly the same density. They only differ in the way that those populations can connect — as “trees,” or as “web-networks.” The tall building is clearly a tree, with all its structural vulnerabilities.

Unfortunately, at this moment in urban history, the growth of tall buildings around the world is nothing short of explosive. As research is showing, the factors that propel their growth seem to have less to do with best practice knowledge, and apparently more to do with the dynamics of short-term capital, images, branding, and even the egos of their promoters. There is reason to fear that this is not the path to sustainable or resilient cities.

There is yet another related geometric factor -- perhaps a surprising one, but no less important. Just as the structure of public and private spaces forms a web-network in the most vital cities and towns -- a "place network" as it has been called -- the interface between the public and private spaces, the building edges and facades in those vital places, also forms a complex web-network -- a "thicker, tougher, more subtle and more complex" kind of structure.

When we view this kind of structure, we often find it beautiful. It has many deep interrelationships between its parts, many symmetries of different kinds -- not only reflectional or left-right symmetries, but also rotational, translational, scaling and so on, and complex combinations of them.

Alexander explored these kinds of structures in his 2003 book project, The Nature of Order. He noted that modern physics has shown how structures are formed through symmetry-breaking and the formation of new symmetries, typically producing a consistent set of geometries that we can observe in many traditional buildings around the world. These buildings "go together" in a very powerful way, unlike the collection of "sculptural objects" that stand apart from their public realm.

The image at the left is a famous series of photographs by MIT professor Harold Edgerton, showing how the symmetry-breaking process (in this case a dollop of milk striking a thin sheet) can form new geometries with complex characteristics and interrelationships. The new pattern features alternating repetition, local symmetries, levels of scale, and other attributes, all within a complex interrelated whole. Importantly, these properties are emergent from the process, and they are direct consequences of it. The symmetry-breaking of the sphere of milk does not result in a mess, but in the spontaneous formation of new symmetries, and new structures. These are not mere aesthetic phenomena, independent from the structure of the process. (Image courtesy MIT.)

We now know that symmetry-breaking and symmetry-formation are at the core of many fundamental structural processes in the Universe, from galaxies to planets to living structures. (Symmetry and symmetry-breaking are also dynamic topics in physics, cosmology and mathematics -- but alas, not in architecture.)  

Alexander showed how this process also occurs when human craftspeople shape their environments, as they go about placing, relating, articulating, and so on. In both cases, the resulting structure is a densely interconnected network of parts and wholes.

ABOVE: Examples of complex geometries consisting of recurrent patterns, including local symmetries, levels of scale, alternating repetition, and other properties, all interrelated into an organic whole. A map of these relationships would not be a "tree", but rather, a complex web-network. Images by Michael Mehaffy.

At left are two buildings that are superficially similar in some ways: each has reflectional symmetry (or "mirror symmetry"), each has a dominant central entrance, each has a number of repeated elements, and each has what appears to be a tree-like branching of parts. One might say that the two buildings are both tree-like, but are only different in style. We might say that the building on the left side is "modern style," and the one on the right is "traditional," or "historic," or "from another era," and so on.

However, this would miss a crucial point: regardless of historic period or style, they are actually different classes of structure, with different kinds of relationships between their parts. In fact, the building to the left has a simpler tree-like structure between its parts than the one on the right, which has a more complex and nested set of relationships between its parts. This set of relationships forms the characteristic pattern of a web-network.

We can see some of these relationships in the diagram at right, where connecting lines have been added to the facades showing the overlapping relationships between the parts. This reveals that they do indeed exhibit fundamentally different types of geometry, with the one at left forming a simpler tree, and one at right, a much more complex web-network. This structure has nothing to do with the age of the buildings, or the periods from which they come (although there are historic reasons why modern buildings tend to be different).

They are fundamentally different kinds of geometric structures.

Moreover, the difference is not only a matter of aesthetics. It is a deeper pattern of connectivity in reality, that we then experience through our aesthetic perception. We may find a more connected structure beautiful, or appealing, or more comfortable to live around, not because of its artistic symbolism or expressiveness, but because its geometry is a better fit with our lives and needs.

The same is true for the way a building relates to its public realm. In the liveliest neighborhoods with the most vitality, there is often a complex web-network relationship between buildings and surrounding spaces. In the contemporary places that are most unsatisfactory, from a human point of view, this is often not the case.

What is at stake is not our ability to be "modern," or to "reflect the spirit of the age," or, if we choose a different path, to be "out of step with the times." That is a persuasive form of conventional thinking, and one that is overdue for critical re-examination. On the contrary, what is at stake is nothing other than the quality of life in cities, and ultimately, the health of people and planet.

ABOVE: Two different urban environments. Which one seems more alive? In fact, the two structures have fundamentally different geometric characteristics, specifically in the way their parts interconnect, or don't. The buildings at left are standalone "object-buildings," with almost no relationship to their public realm. They are self-contained "trees." The buildings at right are deeply interrelated, and deeply related to the public spaces below. Images: John Lee via Flickr (left), José Barbosa via Pexels (right).

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For more information about the 62nd International Making Cities Livable conference, visit the conference web page at https://www.imcl.online/potsdam-2025.